Stashdev 7788 remove timeout retry logic

This is a replay of https://github.com/atlassian/hazelcast/pull/18 on the `atlassian-integration` branch.
Remove the code to send CallTimeoutException responses from remote operation threads back to the caller to indicate timeout.
These are expensive to deserialize (especially when the contents of the CallTimeoutException are not used for anything anyway), and when
the queue is long can lead to an indefinitely growing queue of retried invocations.
In addition, fix the `IsStillExecutingOperation` to return true when a remote call is stuck in one of the work queues but not yet being acted on by one of the operation threads.